<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<!--立即执行函数-->
<script>
    (function (data){
        alert(data)
    })(123);


    (function (data2){
        alert(data2)
        return '111';
    })();


    var num=(function (data3){
        alert(data3)
        return '111';
    })()

    console.log(num)

</script>
</body>
</html>